Phonographs



1957 E. WENNERBO 2,814,494

PHONOGRAPHS Filed Aug. 24, 1953 INVENTOR 2221K Biz 11021200 ATTORNEYUnited States atent PHONOGRAPHS Erik Wennerbo, Motala, Sweden, assignorto Industrigktiebolaget Luxor, Motala, Sweden, a corporation of wedenApplication August 24, 1953, Serial No. 376,048 Claims priority,application Sweden September 25, 1952 3 Claims. (Cl. 274-9) Thisinvention relates to a phonograph device.

Since now phonograph records recorded at different speeds are marketedthe phonographs have to be constructed to suit these different speeds.The speeds, which now are of current interest, are 78, 45 and 33 /3 R.P. M.

It is an object of this invention to produce a simple device to enablethe phonographs to be regulated to the different speeds.

The invention will hereinafter be described with reference to theaccompanying drawing.

In the drawing:

Fig. 1 is a plan view of a turntable, included in the device accordingto the invention.

Fig. 2 is a side view of this device.

In the drawing 1 designates a turntable, which is rotatably pivotedabout a centering pin 2, which in turn is rotatably pivoted about a pin3, arranged in a plane parallel to the plane of the turntable 1, and ina manner not shown is connected to a control device for the phonograph.

The mounting for the pin 3 consists of a clamp 4 fixed to the undersideof the base plate 5. The turntable is near its periphery supplied withthree rubber pads 6, against which the record rests during thereproduction. Furthermore three concentric n'ngshaped grooves arepressed down in the plane of the turntable near its periphery. Thesegrooves form on the underside of the turntable ringshaped hillsconstituting three driving paths 7, 8 and 9 (corresponding to the speeds33 /3, 45 and 78 R. P. M.) for an intermediate wheel 10, which extendsthrough a recess in the base plate of the phonograph and is rotatablypivoted about a shaft 11, arranged in a plane substantiallyperpendicular to the centering pin 2. This shaft 11 is through an arm 12connected to a speed setting device (not shown) for the phonograph. Bymeans of this device the intermediate wheel is axially displaced to bebrought before the driving paths 7, 8 and 9 respectively. In order tobring the inter-mediate wheel into engagement with these driving paths aspring 13 is arranged, which tends to press the arm 12 upwards againstthe base plate 5.

The intermediate wheel 10, which preferably has its driving rim ofrubber, is further so arranged that it, in dependence of its axiallydisplaced position is in engagement with one of three different sizeddriving wheels 14, 15 and 16 on a shaft 17 belonging to an electricmotor 18, which is fastened to the base plate 5 of the phonograph. Theengagement between the intermediate wheel 10 and the driving wheels 14,15 and 16 is so chosen that it is diametrically opposite to theengagement between the intermediate wheel 10 and the driving paths 7, 8and 9. The intermediate wheel 10 is thereby during the running of thephonograph fixed between its engagement spots which would not be thecase, if as usual the angle between these spots is less than 180. Thearrangement of the intermediate wheel 10 such as it is used in theembodiment here described means great advantages with respect to theeven rotational speed of the turntable.

The mode'of operation of the above described device is as follows:

According to' Figure 2 in the drawing the intermediate wheel 10 IS inengagement with the driving path 9 of the turntable and with the drivingwheel 16 of the shaft 17, whereby by running the motor the driving wheel16 through the intermediate wheel 10 rotates the turntable at 78 R. P.M.

When the playing of a record is endedthe centering pin 2 is given aclockwise rotation about its'pivot 3 by means of a device (not shown)connected to the control device of the phonograpmthereby bringing theturntable away from the intermediate wheel 10, thus disengaging theturntable from this wheel. By influence of the spring 13 the arm 12 isbrought upwards so that also the driving wheel 16 is disengaged from theintermediate wheel. This wheel will now be freely displaceable in itsaxial direction by means of the speed setting device of the phonograph.

If a turntable speed of R. P. M. is desired the intermediate wheel 10 isby means of the last-mentioned device displaced to a position, wheresaid wheel is situated above the driving wheel 15 of the shaft 17, afterwhich movement the centering pin 2 is by the control device rotatedanti-clockwise about its pivot 3. This means that the turntable 1 withits driving path 8 is brought into engagement with the intermediatewheel 10 and presses this wheel to engagement with the driving wheel 15of the shaft 17 against the action of the spring 13. In this positionthe centering pin 2 and thus the turntable 1 are held during the playingof a record by means of a spring not shown. By running the motor 18 thedriving wheel 15 of the shaft 17 through the intermediate wheel 10 nowrotates the turntable at 45 R. P. M.

If a turntable speed of 33 /3 R. P. M. is desired the intermediate wheel10 is by means of the speed setting device displaced to a position,where said wheel is situated above the driving wheel 14 of the shaft 17,after which movement the intermediate wheel 10 is, in an analogous wayas is described here above, brought into engagement with the drivingpath 7 of the turntable 1 and the driving wheel 14. By running the motorsaid wheel 14 through the intermediate wheel 10 now rotates theturntable at 33 /3 R. P. M.

In the embodiment described above the power transmission is constitutedby an intermediate wheel 10 engaging on one hand the driving wheels 14,15 and 16 respectively of the shaft 17 and on the other hand the drivingpaths 7, 8 and 9 respectively of the turntable 1. By this arrangement adouble effect is obtained so that to have a desired turntable speed itis not necessary to displace the intermediate wheel so long a distanceas the case would be if the intermediate wheel in its various axialpositions engages a driving wheel with equal sized diameter and ifthereby the different speeds of the turntable are obtained only byengaging the intermediate wheel with the turntable in differentdistances from its rotational centre. However this is possible withoutdeparting from the scope of invention.

The invention has here been described in connection with a single recordplayer. Of course it is also possible to use it for a record changer.

Various modifications of the devices described above are of coursepossible within the scope of the appended claims.

What I claim is:

1. A phonograph comprising a turntable for supporting horizontally arecord during its reproduction, a centering pin for passing through thecenter hole of the record, concentric ring-shaped projections beneathand near the periphery of the turntable to form a plurality of drivingpaths of different diameters, a base plate beneath the turntable andpivotally supporting the centering pin and turntable, a motor fastenedto the base plate and having its shaft extending in a planesubstantially parallel to the plane of the turntable, a plurality ofdriving wheels of different sizes mounted longitudinally on said shaftand in vertical alignment with the concentric rings respectively, avertically arranged intermediary wheel passing through a recess in thebase plate and is laterally displaceable along said shaftto be broughtin operative relationship with any one of said driving wheels and withthe corresponding ring-shaped projection of the turntable, whereby theturntable may be rotated at difierent speeds suitable for difierenttypes of records and whereby the turntable and pivotal centering pin maybe tilted to disengage the turntable from the intermediary wheel.

2. A phonograph as set forth in claiml, wherein the point of engagementof the motor shaft withthe intermediary wheel is spaced about 180 fromthe point of contact of the intermediary wheel with the turntablewhereby an even run of the turntable and a corresponding improved soundreproduction of the record is obtained.

3. A phonograph as set forth in claim 1, wherein said intermediary wheelis rotatably mounted on a shaft, the axis of which is perpendicular tothe centering pin, and spring means for resiliently urging theintermediary wheel with any one of the driving paths of the turntable.

References Cited in the file of this patent UNITED STATES PATENTS1,924,287 Piazze Aug. 29, 1933 2,047,733 Harrison July 14', 19362,438,265 Metzner Mar. 23, 1948

